From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 771D8C4320A for ; Thu, 26 Aug 2021 07:19:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DDC261053 for ; Thu, 26 Aug 2021 07:19:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239888AbhHZHUC (ORCPT ); Thu, 26 Aug 2021 03:20:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234415AbhHZHUA (ORCPT ); Thu, 26 Aug 2021 03:20:00 -0400 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04104C061757; Thu, 26 Aug 2021 00:19:14 -0700 (PDT) Received: by mail-pf1-x431.google.com with SMTP id r13so1591705pff.7; Thu, 26 Aug 2021 00:19:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=cfTbP5ybrHUjQ7XFW8ZJxXbueJDV7DVUr/15F0i3NDo=; b=qsPLTdx3TKdjAIHR1a3Lpi29cmO2138kSw6i/7eLSZ21Qz/yj3oaVRLQybvk64OltB OyFW+PGCeLztsy5DjLaxwE0F30yleyijeG2TQ3Bb7zArd4GNgAmUeOMSVVnDjuxVNJ/y AyPTf8PCMdlLWS29BABilWgNSxOSeIiZyH27e3VaxuiiV3dFm8Efq/24LZXsxhwIiZ9I dPYUi4LG9XplV5p1KEqZl2svhbbw3kKSCbfQv63kF83Joq4DmrRxz9DP9nczm0Q3q1AH j15mLXR8hy7IuN/cmVjNfaUeNhOulF5+T2HSXgsaPJcFJQBTI4X6VtzyMvL5D8xGlJ7j +FlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=cfTbP5ybrHUjQ7XFW8ZJxXbueJDV7DVUr/15F0i3NDo=; b=Ljy9sizGjCNlEe9E54rEIkBs3WWGAZQFcICPzyo9TEvPKcrkKQdJiDQhG51WjQjUpc 8ziqbeZYYlO0aOuQZ2vPDpDvSV63nWZqcLdB/p788vubQjZUkQ+PJSROGfq7/+vCzm/k pZB3dnPYSeiG7B3UBAlPIN10qqZ4ZvSpWL7fWKNzSIVy2xqL6ez+lf8h5L3Yz++jxo8Z Z//oe7Ng6hWB3RIgfjrTBUkwgOkjzmo0q2vnQVQH4aOGQMf3aIedZo2sXCjLfLOdeHbw DBqws9Jv+5lzbrV/Hcwn4Y3kd2s2u1VIbO/FZ19BCf8cSX5/8yJ0EiwwaSKcePZ6RkfM y4Yw== X-Gm-Message-State: AOAM532rkFYch4bO4WlYX0RdYNRoniATVoCU29WP2fvE7SV/K1jIE+n6 LyCU2MhH17kWojngRl5BYkg= X-Google-Smtp-Source: ABdhPJwjYkHzvWF/14P68/Pk5wQjZHR0hGFvjg4FXqdpP/TlcHUtLyTjUWVhyiwV+J6iR/rGPVPLWA== X-Received: by 2002:a65:494e:: with SMTP id q14mr2163360pgs.314.1629962353519; Thu, 26 Aug 2021 00:19:13 -0700 (PDT) Received: from jianchwadeMacBook-Pro.local ([154.86.159.245]) by smtp.gmail.com with ESMTPSA id 6sm1772171pjz.8.2021.08.26.00.19.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 26 Aug 2021 00:19:13 -0700 (PDT) Subject: Re: [PATCH V3 2/5] ext4: add new helper interface ext4_try_to_trim_range() To: Theodore Ts'o Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, adilger.kernel@dilger.ca References: <20210724074124.25731-1-jianchao.wan9@gmail.com> <20210724074124.25731-3-jianchao.wan9@gmail.com> From: Wang Jianchao Message-ID: <43615c43-6837-dd84-c5d8-017596a59688@gmail.com> Date: Thu, 26 Aug 2021 15:19:10 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/8/13 1:44 AM, Theodore Ts'o wrote: > On Sat, Jul 24, 2021 at 03:41:21PM +0800, Wang Jianchao wrote: >> From: Wang Jianchao >> >> There is no functional change in this patch but just split the >> codes, which serachs free block and does trim, into a new function >> ext4_try_to_trim_range. This is preparing for the following async >> backgroup discard. >> >> Reviewed-by: Andreas Dilger >> Signed-off-by: Wang Jianchao >> --- >> fs/ext4/mballoc.c | 102 ++++++++++++++++++++++++++-------------------- >> 1 file changed, 57 insertions(+), 45 deletions(-) >> >> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c >> index 018d5d3c6eeb..e3844152a643 100644 >> --- a/fs/ext4/mballoc.c >> +++ b/fs/ext4/mballoc.c >> @@ -6218,6 +6218,54 @@ __acquires(bitlock) >> return ret; >> } >> >> +static int ext4_try_to_trim_range(struct super_block *sb, >> + struct ext4_buddy *e4b, ext4_grpblk_t start, >> + ext4_grpblk_t max, ext4_grpblk_t minblocks) >> +{ >> + ext4_grpblk_t next, count, free_count; >> + void *bitmap; >> + int ret = 0; >> + >> + bitmap = e4b->bd_bitmap; >> + start = (e4b->bd_info->bb_first_free > start) ? >> + e4b->bd_info->bb_first_free : start; >> + count = 0; >> + free_count = 0; >> + >> + while (start <= max) { >> + start = mb_find_next_zero_bit(bitmap, max + 1, start); >> + if (start > max) >> + break; >> + next = mb_find_next_bit(bitmap, max + 1, start); >> + >> + if ((next - start) >= minblocks) { >> + ret = ext4_trim_extent(sb, start, next - start, e4b); >> + if (ret && ret != -EOPNOTSUPP) >> + break; >> + ret = 0; >> + count += next - start; >> + } > > "ret" is only used inside the if statement, so this might be better as: > >> + if ((next - start) >= minblocks) { >> + int ret = ext4_trim_extent(sb, start, next - start, e4b); >> + >> + if (ret && ret != -EOPNOTSUPP) >> + break; >> + count += next - start; >> + } > > ... and then drop the "int ret = 0" above. > > Otherwise, looks good. > OK, I'll do it in next version Thanks so much Jianchao > - Ted >